Bicycle frame



FIG. 1 is a front, left, side, perspective view of a first embodiment of our new design for a bicycle frame;

FIG. 2 is a rear, right, side, perspective view thereof;

FIG. 3 is a rear, left, side, perspective view thereof;

FIG. 4 is a left, side, perspective view of a second embodiment of the bicycle frame of our new design;

FIG. 5 is a top, front, left, side, perspective view of FIG. 4;

FIG. 6 is a rear, perspective view of FIG. 4; and,

FIG. 7 is a rear, right, side, perspective view of FIG. 4.

The showing of the color contrast in FIGS. 1-3 is illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a bicycle frame, as shown and described. 